llvm dev - Mar 2014 - [LLVMdev] [cfe-dev] C++11 reverse iterators (was C++11 is here)

On Sun, Mar 2, 2014 at 9:26 PM, Chris Lattner <sabre at nondot.org> wrote:
>
> On Mar 2, 2014, at 8:53 PM, Renato Golin <renato.golin at linaro.org>
wrote:
>
> > On 3 March 2014 12:32, Pete Cooper <peter_cooper at apple.com>
wrote:
> >> Would those work with a foreach construct? Perhaps I forgot to
mention
> that was what I'm trying to work out here.
> >>
> >> In example 3 I was wondering if we could define a method
reverse(). We
> could use sfinae to wrap that around rbegin/rend if people like that style?
> >
> > Sorry, I was too terse... ;)
> >
> > If MF is a reverse_iterator, it'd just work, no? But to get the
> > reverse iterator, I think reverse() would be the best general pattern,
> > since you can adapt it to each container needs.
>
> I'm not aware of the prior art or standards are here, but I think that
a
> global reverse() adapter is the way to go.  Likewise, we should have a
> standard "enumerate()" adaptor like python.

I definitely prefer the global adaptor pattern.  As for prior art, I had
played with it a bit, and came up with
https://gist.github.com/compnerd/5694186 a while back.

> -Chris
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>


-- 
Saleem Abdulrasool
compnerd (at) compnerd (dot) org
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On Sun, Mar 2, 2014 at 10:13 PM, Saleem Abdulrasool
<compnerd at compnerd.org>wrote:
> On Sun, Mar 2, 2014 at 9:26 PM, Chris Lattner <sabre at nondot.org>
wrote:
>
>>
>> On Mar 2, 2014, at 8:53 PM, Renato Golin <renato.golin at
linaro.org> wrote:
>>
>> > On 3 March 2014 12:32, Pete Cooper <peter_cooper at
apple.com> wrote:
>> >> Would those work with a foreach construct? Perhaps I forgot to
mention
>> that was what I'm trying to work out here.
>> >>
>> >> In example 3 I was wondering if we could define a method
reverse(). We
>> could use sfinae to wrap that around rbegin/rend if people like that
style?
>> >
>> > Sorry, I was too terse... ;)
>> >
>> > If MF is a reverse_iterator, it'd just work, no? But to get
the
>> > reverse iterator, I think reverse() would be the best general
pattern,
>> > since you can adapt it to each container needs.
>>
>> I'm not aware of the prior art or standards are here, but I think
that a
>> global reverse() adapter is the way to go.  Likewise, we should have a
>> standard "enumerate()" adaptor like python.
>
>
> I definitely prefer the global adaptor pattern.  As for prior art, I had
> played with it a bit, and came up with
> https://gist.github.com/compnerd/5694186 a while back.
>
Yea, there is a pretty strong move toward range adaptors. If possible, I'm
going to work on contributing a basic selection of them to LLVM's ADT
specifically to address the immediate needs of range-based for loops.
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On Mar 2, 2014, at 10:27 PM, Chandler Carruth <chandlerc at google.com>
wrote:
> 
> On Sun, Mar 2, 2014 at 10:13 PM, Saleem Abdulrasool <compnerd at
compnerd.org> wrote:
> On Sun, Mar 2, 2014 at 9:26 PM, Chris Lattner <sabre at nondot.org>
wrote:
> 
> On Mar 2, 2014, at 8:53 PM, Renato Golin <renato.golin at linaro.org>
wrote:
> 
> > On 3 March 2014 12:32, Pete Cooper <peter_cooper at apple.com>
wrote:
> >> Would those work with a foreach construct? Perhaps I forgot to
mention that was what I'm trying to work out here.
> >>
> >> In example 3 I was wondering if we could define a method
reverse(). We could use sfinae to wrap that around rbegin/rend if people like
that style?
> >
> > Sorry, I was too terse... ;)
> >
> > If MF is a reverse_iterator, it'd just work, no? But to get the
> > reverse iterator, I think reverse() would be the best general pattern,
> > since you can adapt it to each container needs.
> 
> I'm not aware of the prior art or standards are here, but I think that
a global reverse() adapter is the way to go.  Likewise, we should have a
standard "enumerate()" adaptor like python.
> 
> I definitely prefer the global adaptor pattern.  As for prior art, I had
played with it a bit, and came up with https://gist.github.com/compnerd/5694186
a while back.
> 
> Yea, there is a pretty strong move toward range adaptors. If possible,
I'm going to work on contributing a basic selection of them to LLVM's
ADT specifically to address the immediate needs of range-based for loops.
Sounds good.  We also have to decide what to do with Function::arg_begin() for
example (and all the other secondary ranges hanging off IR and other things). 
IMO, "for (auto &arg : F.getArguments())" makes the most sense.

-Chris
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On 2014 Mar 2, at 22:27, Chandler Carruth <chandlerc at google.com> wrote:
> 
> On Sun, Mar 2, 2014 at 10:13 PM, Saleem Abdulrasool <compnerd at
compnerd.org> wrote:
> On Sun, Mar 2, 2014 at 9:26 PM, Chris Lattner <sabre at nondot.org>
wrote:
> 
> On Mar 2, 2014, at 8:53 PM, Renato Golin <renato.golin at linaro.org>
wrote:
> 
> > On 3 March 2014 12:32, Pete Cooper <peter_cooper at apple.com>
wrote:
> >> Would those work with a foreach construct? Perhaps I forgot to
mention that was what I'm trying to work out here.
> >>
> >> In example 3 I was wondering if we could define a method
reverse(). We could use sfinae to wrap that around rbegin/rend if people like
that style?
> >
> > Sorry, I was too terse... ;)
> >
> > If MF is a reverse_iterator, it'd just work, no? But to get the
> > reverse iterator, I think reverse() would be the best general pattern,
> > since you can adapt it to each container needs.
> 
> I'm not aware of the prior art or standards are here, but I think that
a global reverse() adapter is the way to go.  Likewise, we should have a
standard "enumerate()" adaptor like python.
> 
> I definitely prefer the global adaptor pattern.  As for prior art, I had
played with it a bit, and came up with https://gist.github.com/compnerd/5694186
a while back.
> 
> Yea, there is a pretty strong move toward range adaptors. If possible,
I'm going to work on contributing a basic selection of them to LLVM's
ADT specifically to address the immediate needs of range-based for loops.
There’s a decent selection of range adaptors in Boost.Range [1].  I’m not sure
the license [2] allows copying the source (IANAL), but any reason not use the
same names?  I don’t see any reason to reinvent the wheel here.

[1]:
http://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/adaptors/reference.html
[2]: http://www.boost.org/users/license.html